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[2620:137:e000::1:20]) by mx.google.com with ESMTP id u15-20020a170902e5cf00b001a9b9c32ab7si3667236plf.624.2023.05.10.00.02.45; Wed, 10 May 2023 00:02:57 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=arm.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236186AbjEJGzt (ORCPT + 99 others); Wed, 10 May 2023 02:55:49 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54394 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236013AbjEJGzs (ORCPT ); Wed, 10 May 2023 02:55:48 -0400 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 7F3B235A5; Tue, 9 May 2023 23:55:25 -0700 (PDT) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 7F9151063; Tue, 9 May 2023 23:56:09 -0700 (PDT) Received: from [10.57.22.157] (unknown [10.57.22.157]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 8B3593F663; Tue, 9 May 2023 23:55:22 -0700 (PDT) Message-ID: <94e7bbaa-3a25-6634-f5af-fff4932a44b9@arm.com> Date: Wed, 10 May 2023 07:55:23 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.10.0 Subject: Re: [PATCH 10/17] PM: EM: Add runtime update interface to modify EM power Content-Language: en-US To: Pierre Gondois Cc: dietmar.eggemann@arm.com, rui.zhang@intel.com, amit.kucheria@verdurent.com, amit.kachhap@gmail.com, daniel.lezcano@linaro.org, viresh.kumar@linaro.org, len.brown@intel.com, pavel@ucw.cz, ionela.voinescu@arm.com, linux-pm@vger.kernel.org, rostedt@goodmis.org, linux-kernel@vger.kernel.org, rafael@kernel.org, mhiramat@kernel.org References: <20230314103357.26010-1-lukasz.luba@arm.com> <20230314103357.26010-11-lukasz.luba@arm.com> From: Lukasz Luba In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Spam-Status: No, score=-4.6 required=5.0 tests=BAYES_00,NICE_REPLY_A, RCVD_IN_DNSWL_MED,SPF_HELO_NONE,SPF_NONE,T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Pierre, On 4/11/23 16:40, Pierre Gondois wrote: > Hello Lukasz, > > On 3/14/23 11:33, Lukasz Luba wrote: >> Add an interface which allows to modify EM power data at runtime. >> The new power information is populated by the provided callback, which >> is called for each performance state. The CPU frequencies' efficiency is >> re-calculated since that might be affected as well. The old EM memory >> is going to be freed later using RCU mechanism. >> >> Signed-off-by: Lukasz Luba >> --- >>   include/linux/energy_model.h |   8 +++ >>   kernel/power/energy_model.c  | 109 +++++++++++++++++++++++++++++++++++ >>   2 files changed, 117 insertions(+) >> >> diff --git a/include/linux/energy_model.h b/include/linux/energy_model.h >> index a616006a8130..e1772aa6c843 100644 >> --- a/include/linux/energy_model.h >> +++ b/include/linux/energy_model.h >> @@ -202,6 +202,8 @@ struct em_data_callback { >>   struct em_perf_domain *em_cpu_get(int cpu); >>   struct em_perf_domain *em_pd_get(struct device *dev); >> +int em_dev_update_perf_domain(struct device *dev, struct >> em_data_callback *cb, >> +                  void *priv); >>   int em_dev_register_perf_domain(struct device *dev, unsigned int >> nr_states, >>                   struct em_data_callback *cb, cpumask_t *span, >>                   bool microwatts); >> @@ -382,6 +384,12 @@ static inline int em_pd_nr_perf_states(struct >> em_perf_domain *pd) >>   { >>       return 0; >>   } >> +static inline >> +int em_dev_update_perf_domain(struct device *dev, struct >> em_data_callback *cb, >> +                  void *priv) >> +{ >> +    return -EINVAL; >> +} >>   #endif >>   #endif >> diff --git a/kernel/power/energy_model.c b/kernel/power/energy_model.c >> index 87962b877376..e0e8fba3d02b 100644 >> --- a/kernel/power/energy_model.c >> +++ b/kernel/power/energy_model.c > > [snip] > >> @@ -531,9 +628,21 @@ void em_dev_unregister_perf_domain(struct device >> *dev) >>       tmp = pd->runtime_table; >> +    /* >> +     * Safely destroy runtime modifiable EM. By using the call >> +     * synchronize_rcu() we make sure we don't progress till last user >> +     * finished the RCU section and our update got applied. >> +     */ >>       rcu_assign_pointer(pd->runtime_table, NULL); >>       synchronize_rcu(); >> +    /* >> +     * After the sync no updates will be in-flight, so free the old >> +     * memory. >> +     */ >> +    if (tmp->state != pd->table) >> +        kfree(tmp->state); >> + > > NIT: I think that the call 'kfree(pd->default_table->state)' which is > done in > the patch: >   PM: EM: Refactor struct em_perf_domain and add default_table > should be done here, otherwise this bit of memory is not freed. In this patch 10/17 there is no 'default_table' field yet, so cannot be freed in this patch's code. > > Regards, > Pierre > > >>       kfree(tmp); >>       kfree(dev->em_pd->table); ^^^^ in this current code we have the clean-up. Here we clean the dev->em_pd->table, which is our conceptual 'default_table' in current code (before refactoring in 13/17) In the patch 13/17 that you was referring to, there is also similar but new cleaning process: ------------------->8--------------------------- - kfree(dev->em_pd->table); + kfree(pd->default_table->state); + kfree(pd->default_table); ------------------8<---------------------------- So, it should be good. Regards, Lukasz